Tube pattern for a refrigerator evaporator

ABSTRACT

A tube pattern for a refrigerator evaporator including tubes in the tube pattern that are staggered in air flow, and an outer diameter of the tubes is in the range of 6.5 mm to 7.5 mm.

FIELD

The present disclosure relates to a tube pattern for a refrigerator evaporator, and also relates to a refrigerator evaporator equipped with the tube pattern.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

The cost pressure in household appliance market is extremely intense, and the increasingly strict governmental regulations are requiring the household appliance to possess even higher energy efficiency, which drives demands for more cost-beneficial and more efficient components.

In the 1990's, the tube used for a refrigerator evaporator in most of the markets was modified in its outer diameter from 9.5 mm to 8.0 mm to Improve the return flow of oil being utilized with new refrigerants. Although some improvements in performance were noticed, such change has not been well understood.

It is generally known that when the diameter of a tube is decreased, the wall thickness thereof and the material consumption are also reduced, with the burst pressure being maintained. A variety of heat transfer models would suggest that it may or may not improve the heat transfer by reducing the tube diameter within the operation area of the refrigerator, but the previous change in diameter has suggested that it may involve certain improvement.

One of the severe uncertainties in further decreasing the diameter is its unknown influence to the compressor. The refrigerator evaporator is working at a condition near atmosphere pressure or of slight vacuum. When the pressure approaches absolute zero, the influence to the compressor increases, so that any increase in the pressure drop may heavily influence the compressor.

In order to reduce global warming, flammable refrigerants are becoming more prevalent in the market. It is desired to minimize the amount of refrigerants used in these applications, and in some cases government regulation limits the amount of refrigerant that can be used.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure primarily utilizes two types of measurement criteria to evaluate the improvement thereof. One criteria is the U·A value per pound of aluminum (where U is an overall heat transfer coefficient and A is an area), embodied in a heat transfer amount obtained per material usage. The other criteria is U·A value per volume, representing a heat transfer amount that can be obtained from a given space. The present disclosure aims to determine the tube outer diameter and tube pattern, thereby maximuming the U·A/lb of aluminum and the U·A per volume, while minimizing the influence to the compressor and optimizing the entire energy efficiency.

According to one aspect of the present disclosure, a tube pattern for a refrigerator evaporator is characterized in that tubes of the tube pattern are staggered in airflow, and an outer diameter of the tubes ranges from 6.5 mm to 7.5 mm. For example, the outer diameter of tube may be 7.00 mm (hereinafter the tube with an outer diameter of Xmm is referred to as an Xmm tube).

A wall thickness of the tubes may range from 0.3 mm to 0.7 mm, as required by a burst pressure. A greater wall thickness may also be used to reduce internal volume and refrigerant charge.

A bending radius at a bending center of the tubes may range from 18.0 mm to 22.0 mm.

According to another aspect of the present disclosure, the evaporator is arranged with 1 column of tubes at every evaporator depth of 25 mm. Then an evaporator with an evaporator depth of 75 mm is arranged with 3 columns of tubes; and an evaporator with an evaporator depth of 50 mm is arranged with 2 columns of tubes.

According to yet another aspect of the present disclosure, the evaporator is arranged with 1 column of tubes at every evaporator depth of 20 mm. Then an evaporator with an evaporator depth of 60 mm is arranged with 3 columns of tubes.

Tubes in the tube pattern are arranged in an inclined orientation with respect to the evaporator depth.

According to the present disclosure, a refrigerator evaporator including the above-mentioned tube pattern for a refrigerator evaporator may be provided.

Based on the construction above, the present disclosure realizes a determination of the tube outer diameter and the tube pattern, thereby maximizing U·A/lb of aluminum and U·A per volume, while minimizing the influence to the compressor performance and optimizing the entire energy efficiency. It also reduces the amount of refrigerant charge required, which can further improve performance by reducing cyclic losses and offers benefits when flammable refrigerants are utilized.

There has thus been outlined certain embodiments of the present disclosure so that the detailed description thereof herein may be better understood, and so that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the present disclosure that will be described below and which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment in detail, it is to be understood that the present disclosure is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The present disclosure is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present disclosure. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do hot depart from the spirit and scope of the present disclosure.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

All the technical features of the present disclosure will become more apparent from the accompanying drawings. The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 shows an evaporator with a depth of 75 mm and 3 columns of tubes;

FIG. 2 shows an evaporator with a depth of 50 mm and two columns of tubes;

FIG. 3 shows an evaporator with a depth of 60 mm and three columns of tubes;

FIG. 4 shows an evaporator with a depth of 100 mm and four columns of tubes;

FIG. 5 through FIG. 7 show the evaluation of influence to the heat transfer performance caused by the tube outer diameter, representing three types of tubes with different outer diameters which are 6.35 mm, 8.00 mm and 9.50 mm, respectively;

FIG. 8 and FIG. 9 show the comparison between a 7.00 mm tube and a 8.00 mm tube arranged on an evaporator with a depth of 50 mm and 2 columns of tubes;

FIG. 10 and FIG. 11 show the comparison between an evaporator with a depth of 50 mm and 2 columns of 8 mm tubes and an evaporator with a depth of 60 mm and 3 columns of 7 mm tubes.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings. For those skilled in the art, all the features and advantage of the present utility model will become more apparent from the accompanying drawings and corresponding description.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The present disclosure provides a tube pattern for a refrigerator evaporator or a freezer evaporator. That is, the evaporator may be used on stand-alone refrigerators, refrigerators that also include a freezer, and stand-alone freezers. In the tube pattern, tubes 1 are staggered in air flow, thereby providing optimal heat transfer. The outer diameter of the tubes 1 ranges from 6.5 mm to 7.5 mm, and the wall thickness of the tubes 1 is decreased and ranges from 0.3 mm to 0.7 mm as required by a burst pressure, so that the material cost can be reduced or to further reduce internal volume and reduce the required refrigerant charge.

A bending radius at a bending center of the tubes ranges from 18.0 mm to 22.0 mm, so that the tubes can be bent at the bending center as tightly as possible with high bending quantity.

According to another aspect of the present disclosure, as shown in FIG. 1 and FIG. 2, an evaporator is arranged with one column of tubes at every depth 2 of 25 mm; that is, the evaporator with a depth of 75 mm as shown in FIG. 1 is arranged with three columns of tubes; and the evaporator with a depth of 50 mm as shown in FIG. 2 is arranged with two columns of tubes.

According to yet another aspect of the present disclosure, as shown in FIG. 3, the evaporator is arranged with one column of tubes at every depth of 20 mm. Then the evaporator with a depth of 60 mm is arranged with three columns of tubes. According to yet another aspect of the present disclosure, as shown in FIG. 4, the evaporator is arranged with one column of tubes at every depth of 25 mm. Then the evaporator with a depth of 100 mm is arranged with four columns of tubes.

As shown in FIGS. 1-3, tubes in the tube pattern are arranged in an inclined orientation with respect to the evaporator depth. The angle of inclination may range between 25 degrees and 60 degrees relative an edge of the evaporator. In the illustrated embodiments, the angle of inclination is about 45 degrees.

Hereinafter the influence to heat transfer performance caused by the outer diameter of the tubes is evaluated by referring to FIG. 5 through FIG. 7. Two types of measurement criteria are primarily used herein. A first criteria is U·A/lb of aluminum, embodied in a heat transfer amount obtained per material usage. A second criteria is U·A per volume, representing a heat transfer amount that can be obtained from a given space.

FIG. 5 through FIG. 7 show three types of tubes with different outer diameters which are 6.35 mm, 8.00 mm and 9.50 mm, respectively; wherein the X-axis in FIG. 5 through FIG. 7 represents CFM (Cubic Feet per Minute); the Y-axis in FIG. 5 represents U·A/lb; the Y-axis in FIG. 6 represents U·A per volume; and the Y-axis in FIG. 7 represents air side pressure drop.

As can be seen from FIG. 5 through FIG. 7, the smaller the outer diameter of the tube is, the higher the U·A/lb of aluminum and U·A per volume are, with the decrease of the air side pressure drop. These factors realize improvement in performance and/or decrease in cost.

As also can be seen from FIG. 5 through FIG. 7, the evaporator arranged with a 6.35 mm tube is similar to the evaporator arranged with 8.00 mm tube in the heat transfer performance. In addition, in several tests of refrigerator evaporators, evaporators provided with 6.35 mm tubes can increase the energy consumption by 4%, on average.

The Applicant found that a 7.00 mm tube can provide beneficial advantages of a decreased tube diameter without any negative influence to the compressor performance, and can maintain the energy efficiency and dramatically reduce the material consumption.

Hereinafter the influences to performance of heat transfer caused by using 7.00 mm tubes and 8.00 mm tubes are evaluated by referring to FIG. 8 through FIG. 11.

FIG. 8 and FIG. 9 show a comparison between a 7.00 mm tube and an 8.00 mm tube arranged on an evaporator with a depth of 50 mm and two columns of tubes. It can be seen that, compared with an 8.00 mm tube, the 7.00 mm tube improves the U·A/lb by 14% and improves the U·A per volume by 12%.

FIG. 10 and FIG. 11 show a comparison between an evaporator with a depth of 60 mm and two columns of 8 mm tubes, and an evaporator with a depth of 60 mm and three columns of 7 mm tubes.

As it can be seen from FIG. 10 and FIG. 11, the 7 mm tube is designed to have a U·A/lb (the heat transfer amount obtained per material usage) higher than that of an 8 mm tube by 33%, and have a U·A per volume (the heat transfer amount that can be obtained from a given space) higher than that of the 8 mm tube by 31%.

While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various examples is expressly contemplated herein, even if not specifically shown or described, so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A tube pattern for a refrigerator evaporator, comprising tubes in the tube pattern that are staggered in air flow, and an outer diameter of the tubes is in the range of 6.5 mm to 7.5 mm.
 2. The tube pattern for a refrigerator evaporator according to claim 1, wherein a bending radius at a bending center of the tubes is in the range of 18.0 mm to 22.0 mm.
 3. The tube pattern for a refrigerator evaporator according to claim 1, wherein the evaporator is arranged with a single column of the tubes at every evaporator depth of 25 mm.
 4. The tube pattern for a refrigerator evaporator according to claim 3, wherein the evaporator has an evaporator depth of 75 mm, and is provided with three columns of the tubes.
 5. The tube pattern for a refrigerator evaporator according to claim 3, wherein the evaporator has an evaporator depth of 50 mm, and is provided with two columns of the tubes.
 6. The tube pattern for a refrigerator evaporator according to claim 3, wherein the evaporator has an evaporator depth of 100 mm, and is provided with four columns of the tubes.
 7. The tube pattern for a refrigerator evaporator according to claim 1, wherein the evaporator is arranged with a single column of the tubes at every evaporator depth of 20 mm.
 8. The tube pattern for a refrigerator evaporator according to claim 7, wherein the evaporator has an evaporator depth of 60 mm, and is provided with three columns of tubes.
 9. The tube pattern for a refrigerator evaporator according to claim 1, wherein the outer diameter of the tubes is 7.00 mm.
 10. The tube pattern for a refrigerator evaporator according to claim 1, wherein a wall thickness of the tubes is in the range of 0.3 mm to 0.7 mm.
 11. The tube pattern for a refrigerator evaporator according to claim 3, wherein the tubes in the tube pattern are arranged in an inclined orientation, with respect to an evaporator depth.
 12. The tube pattern for a refrigerator evaporator according to claim 6, wherein the tubes in the tube pattern are arranged in an inclined orientation, with respect to an evaporator depth.
 13. A refrigerator evaporator comprising the tube pattern for a refrigerator evaporator according to claim
 1. 14. The tube pattern for a refrigerator evaporator according to claim 1, wherein a tube spacing between columns of the tube is smaller or larger than a bend diameter within a column of the tubes. 